Conventionally, as a slide fastener with a separable bottom end stop, there has been known a slide fastener with a side open type separable bottom end stop that is capable of coupling left and right element rows by allowing an insert member disposed on one end of one element row to be inserted into and engaged with a pivot support member disposed on an end portion of the other element row from the side of the pivot support member.
Further, as a slide fastener with such a side open type separable bottom end stop, a slide fastener in which usability of the bottom end stop is improved is disclosed, for example, in Japanese Patent Application Laid-Open No. 2008-43568 (Patent Document 1).
As illustrated in FIG. 10, a slide fastener 61 with a separable bottom end stop 62 disclosed in Patent Document 1 includes a pair of left and right fastener stringers 66 in which element rows 65 are formed such that a plurality of independent synthetic resin fastener elements 64 are lined on left and right fastener tapes 63, a separable bottom end stop 62 disposed on one end portion of the element rows 65, and a slider (not shown).
In the slide fastener 61, the fastener element 64 is formed in a predetermined shape by performing injection molding on the fastener tape 63. As the slider that allows the element row 65 including the fastener elements 64 to pass through, a general slider that has been known in the past can be used.
The separable bottom end stop 62 includes an insert member 67 that is formed continuously from the element row 65, disposed at a lower end portion of the left fastener tape 63, and serves as an insert pin and a pivot stopper body 68 that is disposed at a lower end portion of the right fastener tape 63 and serves as a box pin and a box.
The insert member 67 includes an insert plate portion 67a of a thin plate form fixed to both front and back surfaces of the left fastener tape 63, a to-be-pivoted portion 67b (a pivot shaft portion) that is disposed to protrude in a tape front-back direction at a leading end portion (a rear end portion) of the insert plate portion 67a at a tape end portion side, a projecting portion 67c formed along the tape inner side edge of the insert plate portion 67a, a coupling portion (hook portion) 67d disposed at an end portion (a front end portion) of the insert plate portion 67a at the element row 65 side, and a recess portion 67e formed on the front and rear surfaces of the insert plate portion 67a. 
Both the front and rear surfaces of the insert plate portion 67a are flat except the recess portion 67e, and the thickness of the insert plate portion 67a in the tape front-back direction is set to be smaller than an size of the clearance formed between upper and lower flanges of the slider. The insert plate portion 67a has a notch portion 67f that is cut toward the inside of the tape from the tape end portion side.
The pivot stopper body 68 includes a slider holding portion (a box pin portion) 68a that is formed on both front and rear surfaces of the right fastener tape 63, a pivot stopper portion (a box portion) 68c that is formed at a thickness thicker than the slider holding portion 68a via a step portion 68b and has a substantially J shape in the front view, and a reinforcement portion 68d that is formed closer to the tape inner side further than the slider holding portion 68a and increases the strength of fixing of the pivot stopper body 68 to the fastener tape 63. Further, an engaging concave groove 68e that engages the insert plate portion 67a is formed in part of the side surface of the slider holding portion 68a opposite to the insert plate portion 67a and part of the side surface of the pivot stopper portion 68c opposite to the insert plate portion 67a. 
Further, the insert member opposing side edge of the slider holding portion 68a curves such that an intermediate portion thereof slightly expands toward the insert member 67. Further, when the slider slides to come in a contact with the step portion 68b, the slider holding portion 68a can be inserted into an element guide passage of the slider and hold the slider.
The pivot stopper portion 68c includes a pivot space 68f that is opened upward so that the to-be-pivoted portion 67b of the insert member 67 can be engaged or disengaged through the side of the pivot stopper body 68 and an inner peripheral surface 68g that comes in contact with the to-be-pivoted portion 67b inserted into the pivot space 68f and may rotatably engage the to-be-pivoted portion 67b. Further, a slit 68h is formed in a leading end portion of the pivot stopper portion 68c from the inner peripheral surface 68g to the outer peripheral surface. The groove width of the slit 68h in the tape front-back direction is set to be larger than the thickness of the insert plate portion 67a. 
In the slide fastener 61 of Patent Document 1 with the separable bottom end stop 62 including the insert member 67 and the pivot stopper body 68, by inserting the to-be-pivoted portion 67b of the insert member 67 into the pivot stopper body 68 from the side of the pivot stopper body 68 in the state in which the slider is held on the pivot stopper body 68, the to-be-pivoted portion 67b is rotatably engaged with the pivot stopper portion 68c of the pivot stopper body 68.
Then, by rotating the insert member 67 centering on the to-be-pivoted portion 67b toward the pivot stopper body 68 in the state in which the to-be-pivoted portion 67b is engaged with the pivot stopper portion 68c, the insert plate portion 67a of the insert member 67 is inserted into the element guide passage through a tape groove formed between the upper and lower flanges of the slider. Thereafter, by sliding the slider along the element rows 65 in a coupling direction, the coupling portion (hook portion) 67d of the insert member 67 can be first engaged with the fastener element 64 adjacent to the pivot stopper body 68, and the left and right element rows 65 can be further coupled in order starting from the end portion at the separable bottom end stop 62 side.
Meanwhile, in the slide fastener 61, even by inserting the to-be-pivoted portion 67b of the insert member 67 into the pivot stopper body 68 from a shoulder mouth of the slider through the element guide passage of the slider in the state in which the slider (not shown) is held on the pivot stopper body 68, the to-be-pivoted portion 67b is rotatably engaged with the pivot stopper portion 68c of the pivot stopper body 68. Thereafter, by sliding the slider along the element rows 65 in the coupling direction, the left and right element rows 65 can be coupled in the same manner as described above.
That is, in the slide fastener 61 of Patent Document 1, when coupling the left and right element rows 65, the insert member 67 can be rotatably engaged with the pivot stopper body 68 by arbitrarily selecting a first operation of engaging the insert member 67 with the pivot stopper body 68 by directly inserting the to-be-pivoted portion 67b of the insert member 67 from the side of the pivot stopper body 68 or a second operation of engaging the insert member 67 with the pivot stopper body 68 by inserting the to-be-pivoted portion 67b through the element guide passage of the slider, thereby improving operability and convenience of the slide fastener 61.
Patent Document 1: Japanese Patent Application Laid-Open No. 2008-43568